Technical Field
The present invention relates generally to recovery of algal oil. More particularly, the present invention relates to a system and process for culture of algae and extraction of algal oil using high shear.
Background of the Invention
In recent years, algal oil has been recognized as a valuable agricultural land-saving alternative to plant feedstock, such as soybean oil, canola and palm oil or animal, fish and bird fat and tallow. Algae are the simplest plants that live in a water environment. Many algae are unicellular that may or may not have a cell wall. Similar to other plants, algae are photosynthetic. They utilize carbon dioxide as a carbon source and store energy in the form of lipids within the intracellular oil bodies, surrounded by membranes. Algae multiply and grow at a very fast rate and, depending on the genetic background and growth conditions, may have very high oil content. In biodiesel production, the wild type strains of algae or mutants and genetically modified microorganisms, which are designed and selected to produce enhanced levels of oil and/or high levels of oleic acid, are preferred. Such strains can be obtained by Polymerase Chain Reaction (PCR) mutagenesis or by exposure to ultraviolet or ionizing radiation and chemical mutagens. Oil-overproducing strains can be engineered with the help of the directed evolution and other biotechnological techniques known to those skilled in the art.
In addition to methods and systems that stimulate and increase production of oil in algae during culture, there is also the need for methods and systems to extract algal oil. There are a number of methods for disintegration of algae and recovering the algal oil, such as pressing, extraction with organic solvents, enzymatic degradation, lysis using osmosis and ultrasonic and microwave-assisted disruption. Some of the new technologies for algal oil extraction include enzymatic hydrolysis, pulsed electric field (PEF) technology, and the use of amphyphillic solvents.
Clearly, there is a need and interest to continue to develop systems and methods for algal oil extraction. Preferably such systems and methods are economical and able to handle large volume of algal culture.